There presently exists in many industries including papermaking, the need to separate solids from liquids. In this regard, filtering of the liquid provides for a convenient way of providing same. Heretofore as set forth in U.S. Pat. No. 4,412,920, the disclosure of which is incorporated herein by reference, a filtering device is disclosed. This device utilizes a screen having a central opening and a top spray arranged so that the liquid to be filtered flows through the screen. The solids collected are forced along the screen toward a central opening. Thus the separation of the solids from the liquid occurs.
While this device has proven very satisfactory, in certain applications the high volume situations, the solids tend to staple to the screen clogging it. Also if a very fine screen is used a similar problem occurs.
An improvement upon the device shown in the above referenced patent is that set forth in U.S. Pat. No. 5,259,955, the disclosure of which is also incorporated herein by reference. In this latter patent, the performance of the strainer is improved significantly through the application of a vacuum under the screen thereby applying an additional force on the liquid being strained to force it through the screen. To prevent stapling, a high pressure cleansing fluid is directed at the screen at the same time at an angle with the nominal plane or surface of the screen to force the solids strained by the screen to roll towards the center opening before the solids become stapled.
However some problems still exist with the strainers of the type described above. More specifically, the tank supporting the screen and receiving the strained liquid may be tilted slightly which causes an even flow of the liquid/solid mixture onto the screen thus reducing its efficiency. Turbulence in the liquid/solid mixture caused, for example by inlet flow conditions, also may result in an uneven flow.